I find it ironic that the iPod Classic is called Classic when the UI is kinda janky compared to that of an original iPod.
I have a couple of qualms about the somewhat strange behavior behind the iPod Touch/iPhone UI, but they're not as bad.. For example, there's no way to turn off the cover flow mode, so whenever I sit it sideways (and I always do in the car), the play controls are pretty much gone. Second, if you DO use cover flow mode, you find that it goes into album-mode instead of playing your whole library, which is annoying as *@#%.
The last thing is that if you're not in the "all songs" list, there's no way to play your entire library, I guess that's to be expected since the same is sorta true with iTunes, but not entirely - if you sort by artist in iTunes you can still play your entire library. If, OTOH you look up an artist on your iPod, you're going to hear the 1 or 2 songs you have from them over and over and over...
XD
The "Now playing" button gets on my nerves for a similar reason (not entirely sure why), buuut the other killer is, that if the screen goes to sleep you have to hit the menu button TWICE to get controls like fast forward/pause.
Because of that, it's impossible to use an iPod Touch in a car that isn't equipped with a unit to control the iPod through the stereo, in fact you can't even buy a remote because apple doesn't make (and nobody really makes) iPod remotes anymore.
Of course, the touch controls themselves seem a little odd to be operating while driving, but it's not really a big deal - the randomness between having to hit menu twice to bring them up though IS a problem. I know I can hit skip/pause without looking at my iPod Touch, but the fact that it's not going to be there when I tap it, pisses me off.